Atomic Force Microscopy Measurements of the Area Function of a Sphero-Conical Tip

With the improvement of depth-sensing instruments nanoindentation has become a standard tool for the study and design of thin film systems, nanocomposites and other nanostructured materials and devices. Mechanical properties, such as elastic modulus and hardness can be measured at scales in the depth range of tens of nanometers. The correct determination of the mechanical properties depends on the proper evaluation of the real contact area. While two standard methods are commonly used, indentations on a reference sample and measurement by atomic force microscopy (AFM), there are many caveats and the issue remains tricky, especially for large depths. In this contribution we present an example where the standard calibration of the tip area function via a reference sample cannot be used for the desired tip and the AFM method must be used instead.